diff --git a/smtpd_watcher/smtpd_watcher.py b/smtpd_watcher/smtpd_watcher.py
index facfbc4..91c4501 100644
--- a/smtpd_watcher/smtpd_watcher.py
+++ b/smtpd_watcher/smtpd_watcher.py
@@ -54,7 +54,9 @@ class SmtpdWatcher:
             capture_output=True,
         )
         self._log.debug(
-            result.stdout
+            result.stdout,
+            result.returncode,
+            result.stderr
         )
         ips['postfix'] = result.stdout.split(' ')
         self._log.debug(
@@ -205,6 +207,10 @@ class SmtpdWatcher:
             )
             sys.exit(1)
         conn.close()
+        self._log.debug(
+            "Obtained mail users: %s",
+            mail_users
+        )
         return mail_users
 
     def _init_log(self):